public class Bookshelf
{
public static void main(String[] args)
{
Book bk1= new Book("love","smith","great","段志轩20172304");
Book bk2= new Book("beauty","guity","good","strong");
System.out.println(bk1);
System.out.println(bk1.getCook());
bk1.setCook("kuang");

System.out.println(bk1.getCook());
System.out.println(bk1);
}
}
